Rolling,Rolling mills,Rolling processes &Rolling Applications

1. Production Technology:
Rolling
COURSE CODE: C211
REGULATION: R19
2nd BTECH 2nd SEM
PREPARED BY :
POLAYYA CHINTADA M.TECH,M.B.A,(PhD)
ASSISTANT PROFESSOR
LENDI INSTITUTE OF ENGINEERING AND
TECHNOLOGY

2. 2
PRODUCTION TECHNOLOGY
SYLLABUS
UNIT 2:
Metal Forming: Introduction, nature of plastic deformation, hot and cold working of metals,
mechanics of metal forming; Rolling: Principle, types of rolling mill and products, roll
passes, forces in rolling and power requirements; Extrusion: Basic extrusion process and its
characteristics, hot extrusion and cold extrusion, wire drawing, tube drawing
Nature of plastic deformation, cold
and hot working process, working of a
rolling mill
and types, extrusion processes.
COURSE OBJECTIVE:
COURSE OUTCOMES:
APPLICATIONS:
piping and tubes, body
panels, construction materials,
electrical motors, doors,
production of tubes and hollow
pipes,
frames, doors and windows
Compare cold working and hot
working processes. (L4)
● Explain the working of rolling
mills. (L2)
● Evaluate the forces and
power in rolling and extrusion
processes. (L5)

3. • Rolling is the process in which the metals and alloys
are plastically deformed into semi finished or
finished condition by passing between circular
cylinders.
• Due to the frictional forces the metal is drawn into
the opening.
• Metal Changes its shape due to high compressive
forces.
• Both hot(for drastic shape changing) and cold
rolling(for finishing) process are there.
• From the start ingot- blooms- billet- slaps which are
further rolled into plat, sh
Yoe
uca
e
Nt, rod, bar, pipe, rails.
Intro of Rolling

4. Friction in rolling
• It depends on lubrication, work material and also
on the temperature.
• In cold rolling the value of coefficient of friction is
around 0.1 and in warm working it is around 0.2.
• In hot rolling it is around 0.4 In hot rolling sticking
friction condition is also seen and then friction
coefficient is observed up to 0.7.
• In sticking the hot wok surface adheres to roll
and thus the central part of the strip undergoes with a
severe deformation.

5. Classification of Rolling Mills
Classifications based on number of rolls
• Two high rolling mills
• Three high rolling mills
• Four high rolling mills
• Cluster rolling mill
• Planetary rolling mill

6. Two high rolling mills(single direction)
• Constant direction rolling
• This type of mill has two rollers arranged as shown in figure
below. Both the roller revolves at same speed but in opposite
direction. .
• The space between the rollers can be adjusted by raising or
lowering the upper roll which is adjustable.
• To reduce the thickness of work piece, it can be feeded from
one direction only.
• Least expensive
https://www.youtube.com/watch?v=dpbQK7D97H4

7. Three high rolling mills
• This type of rolling mills consists of three rolls arranged one
above other as shown in figure.
• The direction of rotation of upper and lower rolls are same
but the middle roll rotates in the opposite direction.
• This type of rolling mills are used for rolling of continuous
passes in a rolling sequence without reversing the drives.
• This results in a higher rate of production then the two-high
rolling mill.
https://www.youtube.com/watch?v=dpbQK7D97H4
https://www.youtube.com/watch?v=TkVfrM1FSIU

8. Four high rolling mills
• In this type of rolling machine, two rolls are in direct contact with the
work piece and the other two rolls are used as backup rolls.
• The two rolls which are in direct contact with the workpieces are
smaller than backup rolls and are called working rolls.
• Backup rolls are used to prevent the deflection of the smaller rolls,
which otherwise would result in thickening of rolled plates at the
centre.
https://www.youtube.com/watch?v=dpbQK7D97H4

9. Cluster Rolling Mill
• In this type of rolling mill, each of working roll is backed up by two
or more larger backup rolls.
• These rolls are arranged as shown in figure.
• This rolling mill are used in rolling hard thin materials. For rolling
hard thin materials, it may be necessary to employ work rolls of
very small diameter but of considerable length .
• In such cases adequate support of the working rolls can be
obtained by using a cluster-mill.
https://www.youtube.com/watch?v=13dUL9OQFvw
https://www.youtube.com/watch?v=eKyUEqcDl1g

10. Planetary Rolling Mill
•
In this type of rolling mill, a large backup roller is surrounded by
many planetary working rolls.
• Each planetary rolls gives constant reduction. It is used to reduce
large thickness of single pass of steel strip.
• Its rolling capacity is more than cluster rolling mill but less than
rolling mill.

11. Difference between Hot & cold Rolling

12. Advantages & Disadvantages of Rolling
The advantages of Rolling process are as follows.
•By rolling, uniform dimensions of the components
can be obtained.
•It uses the same tool in the sense, the same rollers
are responsible for the production of various
components.
•Close tolerance is possible for the components in
the rolling.
•high-speed production takes place in the rolling.
Advantages of Rolling Process:
The disadvantages of Rolling process are
as follows.
•The cost of equipment is high.
•It is suitable for large scale production
only.
•Poor surface finish and thereby we need to
secondary operations like finishing etc.
Disadvantages of Rolling Process:

13. Applications of rolling:
Rolling is used for making hollow seamless tubes, rods
etc.
Large length cross sections are produced by rolling
process.
It is use for mass production of threaded parts like
screw, bolts etc.
Gears can be cut on gear blank by rolling process.
Construction material, roofing panels, partition beams,
railroads, etc. are rolling product.
It is used in automotive industries for manufacture
various parts.
Rings of turbines, bearing and other machines are
rolling product.
Steel sheets, plates are made by rolling process.

14. Yours:
POLAYYA CHINTADA M.TECH,M.B.A,(PhD)
ASSISTANT PROFESSOR
https://www.youtube.com/watch?v=3iU_Li5tG-0